Problem: Solve for $x$ and $y$ using substitution. ${-2x+6y = -10}$ ${x = y+7}$
Explanation: Since $x$ has already been solved for, substitute $y+7$ for $x$ in the first equation. ${-2}{(y+7)}{+ 6y = -10}$ Simplify and solve for $y$ $-2y-14 + 6y = -10$ $4y-14 = -10$ $4y-14{+14} = -10{+14}$ $4y = 4$ $\dfrac{4y}{{4}} = \dfrac{4}{{4}}$ ${y = 1}$ Now that you know ${y = 1}$ , plug it back into $\thinspace {x = y+7}\thinspace$ to find $x$ ${x = }{(1)}{ + 7}$ ${x = 8}$ You can also plug ${y = 1}$ into $\thinspace {-2x+6y = -10}\thinspace$ and get the same answer for $x$ : ${-2x + 6}{(1)}{= -10}$ ${x = 8}$